1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to a patterning method of a liquid crystal display (LCD) device.
2. Discussion of the Related Art
Among various ultra-thin flat type display devices, which include devices having a display screen with a thickness of not more than a few centimeters, a liquid crystal display (LCD) device can be widely used for notebook computers, monitors, aircraft, etc. since it has advantages such as low power consumption and portability.
The LCD device includes lower and upper substrates facing each other at a predetermined interval therebetween, and a liquid crystal layer formed between the lower and upper substrates. Generally, the lower substrate includes a thin film transistor and a pixel electrode, and the upper substrate includes a black matrix layer, a color filter layer and a common electrode.
The LCD device includes various elements formed by repeated steps. In particular, photolithography may be used to form elements of various shapes. However, forming elements using photolithography requires the use a mask of a predetermined pattern and a photo-irradiation device. Accordingly, photolithography has the disadvantage of increasing manufacturing cost. In addition, photolithography requires complex exposure and development processes increasing the time required for manufacturing LCD devices.
To overcome the problems associated with photolithography, alternative patterning methods such as printing methods are used.
In a printing method, a predetermined material is coated in a desired pattern on a printing roll. By rolling the printing roll on a substrate, the predetermined material of the desired pattern is printed on the substrate. Printing methods employ physical contact between the printing roll and the substrate, which can restrict the applicability of the printing method. In spite of the theses disadvantages, printing methods having various modifications are used because the printing method is simple and advantageous to the mass production of liquid crystal devices.
Hereinafter, a related art printing method will be described with reference to FIGS. 1A to 1C.
FIGS. 1A to 1C are schematic views illustrating a related art printing method.
As shown in FIG. 1A, a pattern material 20 is supplied through a printing nozzle 10, and is coated onto a printing roll 30. The printing roll includes a blanket 35 that adheres to the printing roll 30. The pattern material 20 is coated onto the printing roll blanket 35.
Referring to FIG. 1B, as the printing roll 30 rolls on a printing plate 40 having a plurality of projections 45 of predetermined shape, some of the pattern material 20a is printed on the projections 45 of the printing plate 40, leaving remaining pattern material 20b formed on the blanket 35 of the printing roll 30.
As shown in FIG. 1C, the remaining pattern material 20b is printed on the substrate 50 by rolling the printing roll 30 on the substrate 50.
When the related art printing method is used, problems associated with the blanket 35 adhering to the printing roll 30 may interfere with precisely forming a required pattern on the substrate 50.
Forming precise patterns requires that the blanket 35 have good adherence to the printing roll 30, and that the blanket not exhibit deformation during the printing process. The blanket should also exhibit adequate elasticity during the printing of the pattern material to the substrate 50.
The blanket may be formed of Si-based resin. However, Si-based resin has a low surface tension. The low surface tension of the Si-based resin may result in the pattern material 20 having a swelling portion as shown in ‘A’ of FIG. 1A. The swelling portion ‘A’ of the pattern material interferes with obtaining precise patterns using the printing method of the related art.